Electric current rectifier control system



Aug. 30, 1932. KQBEL 1,873,968 Q ELECTRIC CURRENT RECTIEIER CONTROL SYSTEM Filed Aug. 15. 1930 IIIIIVV lllllll l ll lllll Inventar I 17m Kobe! By g Attorney cated and expenslve.

tifiers in which Patented Aug 30, 1%932 izosrt, or .unnnTBAn-En; SWITZERLAND, nssienon To Anni 1 NGESE-LLSGHAFT 'BItOFIN, BOVERI 8a GIEL, OF BADEN, SWITZERLAND, A JOINT-STOGK COMPANY OF SWITZERLAND Application filed August 15, 1930, Serial No.

a system for controlling theignitionor' attachment of the arc tothe anodes of the rectifier. V I

It is desirable and frequently absolutely necessaryto vary the moment at which the arc is transferred from one anode to another in an electric current rectifier of the metallic vapor type with relation to the alternating current voltage wave. Grids, on which a voltage may be impressed, located adjacent the anodes, are commonly used forthis' purpose and it has alreadybeen proposed to displace the voltage phases of the anodes and their grids relative to each other to per-, mit control of the anode current by the voltage impressedonthe' grids. Phase shifters and special voltage transformers were however required to attain the desired results which made the control system very compli- It is, therefore, among the objects of the present invention to provide a control system for electric current rectifiersof the metallic vapor type in which the moment of attachmerit of the arc to the anodes of the rectifier are positively controllable. V

Another object of the invention is to provide a, control system for electric current rectifiersin which grids are arranged adjacent the anodes of the rectifier an'dare conl nected with and controlled from discharge tubes for the purpose of controlling theattachment of the arc to the anodes.

Another object of the invention is to provide a control system for electric current recdischarge tubes are connected with the anodes of the rectifier and are supplied with a voltage in addition to that of the anodes to control the potential of the grids connected with the tube and thereby control the attachment of the arc to the anodes.

Objects and advantages, other than those above set forth, will be apparent from the following description when read in connec- VI tion with the accompanying drawing in which embodiment of the c nnnornrc ounnnnr nueririnn oon'rnorgsvs'rnlvr 475,503, and in Germany August 15,1929.

Figure 1 diagrammatically illustrates one present invention showing the use of alternating current as the source for the additional grid control voltage, and Figure 2 is a showing the use of a direct current source for the additional grid control voltage. I Referring more particularly to the'drawing by characters 'of reference, the reference numeral 3 designates an'alternating'current 80 supply line connected with the primary winding 4: of a transformer, the secondary winding of which is shown at 5. The several por tions of the star-connected secondary winding 5 are each connected with and supply an al- 65 ternating voltage to anodes 7 enclosedwithin a tank8 also containing a cathode 9' of suitable vaporizable material having a valve action on electric current flowing through the vapor thereof. The electric current rectified 70 during its passage from the anodes 7 to the cathode 9 is supplied to a work or current consuming circuit comprising a conductor 11 connected with the cathode and'with a current consuming devicelfi and a conductor 18 con- 7 nected between the-neutral point of the secpndary winding 5 and the current consumer The circuit for controllingthe flow of curm rentfrom the anodes 7 is formed, as shown 0 inFig. 1, by grids 16 each-of which arear-, ranged within the tank 8 adjacent each of the anodes .7 and are 'adjustably connected through a resistance 17 with the secondary winding 18 of an auxiliary transformer. One 8 end of the secondary winding 18is connectedwith oneof the electrodes of a discharge tube 19 and the otherelectrode thereof is con nected with the portion oft-he 'supply transformer secondary 5 supplying voltage to the 90 anode 7 underconsideration. The primary winding 20 of the auxiliary transformer is connected across the supply line 3 as is customary. It will be understood that only the control system for one anode has been shown andthat the system is to be duplicated for each anode to be controlled;

The modification as si own in Fig. 2 dif' fers from that showiiin Fig. land above described only in the substitutionof a source of modification of'the inventloi- L65 direct current 22 for the transformer 18, 20 without in any way varying the remaining portions of the system or materially altering the principle of its operation.

The operation of the system is believed to be explainable by the following theory. Con sidering an anode at the moment a voltage is impressed thereon by the winding 5, the voltage is" such that the anode becomes positive with respect to the cathode by the amount of the arc drop. The are would then be transferred to the anode now under consideration from the anode previously carrying thearc except for the presence of grids. The grid, at that particular instant, carries a negative charge received from the free electrons moving in the tank 8 and, if the grids are made with a suficiently fine mesh, thereby prevents the anode from receiving the arc. The volt:

, ages of the windings 5 and 18 increasing, and

being in phase, are in excess of the cathode voltage by a certain amount which is applied to theelectrodes of the discharge tube. When such excess voltage reaches the'breakdown voltage of the tube, the tube becomes conductive and'the excess voltage is applied to the resistance 17 and the grid. The grid 16 acts as an anode and takes the arc while the resistance 17 limits the current flowing to the grid. The blocking action of the grid then immediately ceases and anode 7 takes the arc and carries the load circuit. 'The penetration Voltage of the tube may be reached at an earlier point in the alternating current cy cle by increasing the terminal voltage of the winding 18 or battery 22 thereby increasing the average direct current output voltage of the rectifier. The opposite result is, of course, reached by decreasing the terminal voltage of either the winding 18 or the direct current source 22. Such voltage may be adjusted in any desired electrical or mechanical manner and by various well-known means.

Although but two embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

The invention claimed is: V

1. In a system for controlling the operation of an electric current rectifier of the metallic vapor type, a closed tank, anodes extending into said tank, a cathode within said tank, grids arranged adjacent said anodes, an alternating current supply line connected with said anodes, and a discharge tube Connected with each of said anodes and with each of said grids. V 2. In a system for controlling the operation of an electric current rectifier of the metallic vapor type, a closed tank, anodes extending into said tank, grids arranged adjacenthsaid anodes, an alternating current age supplied to said tube.

. supply line connected with said anodes, a discharge tube connected with each of said anodes and with each of said grids, and means for supplying a voltage to said tube in addition to the voltage of said anode.

3. In a system for controlling the operation or an electric current rectifier of the metallic vapor type, a closed tank, anodes extending into said.tank, grids arranged adjacent. said anodes, an alternating current supply line connected with said anodes, a discharge tube connected with each of said anodes and with each of said grids, means for supplying a voltageto said tube in addition to the voltage ofsaid anode,and means for adjusting the value of theadditional volt- 4. In a system for controlling the operation of an electric current rectifier ofthe metallic vaportype, a closed tank, anodes extending into said tank, grids arranged adjacent said anodes, an alternating current supply line connected with said anodes, a dischargetube connected with each of said anodes and grids, the said tubes being supplied with the voltage of said anodes, and an auxiliary transformer connected with and supplying a volt-.

age to each of said tubes and tion to the voltage supplied from said anodes.

5. In a system forcontrollingthe operation of an electric current rectifier of the. metallic vapor type, a closed tank, anodes extend ing into saidtank, grids arranged adjacent said anodes, an alternating current supply line connected with said anodes, tube connectedwith each of said anodes and grids, the said tubes being supplied with the voltage of said anodes,an auxiliary transformer connected with and supplying a voltage to each of said tubes and grids in addition to th voltage supplied from the asso ciated said anode, and a resistance adjustably connecting each said auxiliary transformer and the associated said grids to vary the voltage impressed thereon. V In testimony whereof I have hereunto subscribed, my name this 6thday of August ERNST KOBEL.

a discharge,

grids in addi- 

